On digital scanners having one or more scan modules able to produce a digital representation of an image at rates capable of minimally supporting ten 8.5×11 pages per minute, there is a requirement for the hardware to process and transport the high volume of resultant data. In the normal base configuration, there is a foreseeable set of functions that the manufacturer must minimally provide. This may include pixel correction, gain adjustments, and color correction for example. This functionality will be referred to hereinafter as the Scanner Front End (SFE). The out put of this SFE image chain is then fed into an image buffer. The data representing the images in the image buffer are then communicated to an external host processor over a digital interface.
It is often desirable to do additional, high-end image processing such as image binarization and color drop out in a personality (daughter) card which can optionally be installed in the image chain between the output of the SFE and the image buffer. These daughter cards may be developed by third party manufacturers who want to provide custom, high-end image processing capability for the base scanner.
The shortcoming with this method of delivering high-end imaging capabilities for a digital scanner is that it requires close technical coupling of the development of the scanners embedded firmware and the unknown 3rd party daughter card development. This would be the case if the scanner firmware required knowledge of the potential daughter card functionality to control it. The other potential shortcoming is that the base scanner's implementation artificially constrains the functionality of the daughter card by providing a limited interface.